The invention is related to providing a pilot burner safety device of a gas combustion apparatus for shutting down a gas supply valve automatically at poor oxygen condition, particularly to providing a pilot burner safety device for enhancing reliability during initial ignition operation, in which this safety device has means of automatically controlling the air volume taken in through an intaking hole preventing the occurrence of a flame lifting phenomena, which that at initialized firing excessive air volume adversely influences the mixed gas intended to be at a certain theoretical concentration rate, so that it diminishes the speed of a combustion process to below that of a mixed gas flow.
Nowadays, houses tend to be sealed with the result that indoor ventilation has deteriorated unless there is forced ventilation. Nevertheless, if an open-type instant heater and an indoor convection type heater, etc. are used indoors, it induces a poor oxygen environment, which could cause a person inside to be poisoned by carbon monoxide.
Japan Laid Open Patent Publication No. Sho 57-60113 describes a safety device, preventing accidents caused by a long operation. This device detects the state of a flame heat generated by a flame lifting at poor oxygen conditions during the combustion operation of a main burner. If the detected heat is below the predetermined temperature, it cuts off the electromagnetic force at a gas supply valve through a control circuit to stop the gas supply.
In other words, the flame is formed away from the flame nozzle in a pilot burner, or spaced away in a predetermined distance from the thermocouple adjacent to the flame nozzle, so that the thermocouple is not heated and shuts off the electromagnetic force at the electromagnetic gas supply valve stopping the gas supply, and thereby extinguishing the main burner.
As described below in detail, a pilot burner includes the body, which is perforated through the inner center portion thereof to form a gas supplying passage. Into the gas supplying passage there is a nozzle fitted for jetting gas supplied from a storage vessel. An air supply hole is pierced at a predetermined position along the way of the gas supplying passage of a pilot burner. Therefore, gas from the nozzle is mixed at the predetermined rate with air taken in from the air intaking hole, and the mixed gas is jetted at the flame nozzle located at the front end of a pilot burner to generate the flame at firing.
However, in the pilot burner, the size of the air supply hole is determined to supply necessary air for a normal combustion condition, and through the hole, air is fed in excess over the air volume required for initialized firing. At this time the speed of a mixed gas flow is greater than that of a combustion process, after which a flame is formed away from the flame nozzle of a pilot burner, or a flame lifting phenomena such as that which occurs in a poor oxygen condition happens. Therefore, the heat of a flame is not transferred to the thermocouple adjacent to the flame nozzle, with the result that the electromagnetic force at the valve is shut off. Whereby the electromagnetic gas supply valve is closed when it should be opened. This occurs frequently. The nonignition phenomena cause the user to go through the ignition step several times. Due to it, it may inconvenience a user with unsatisfactory results. The nonignition phenomena occurring at initial firing may result from excess air volume over the desired air volume at initiation
So, the air intaking hole is sized to intake an air volume, rendering the safety device inoperative and not preventing an accident that could result from a poor carbon environment.
In view of the foregoing, it is the object of this invention to provide a pilot burner safety device of a gas combustion apparatus having a safety aspect of automatically, controlling the intaking air volume required for firing in accordance with the initial ignition or normal combustion operation automatically and then stopping supply gas at poor oxygen condition, and preventing the nonignition phenomena at initial ignition, to achive a firing at the first ignition operation.